Heater motor help needed!!!!

[Mattmoss]

Hi chaps,

I'm after some advice with regard to the heater motor on my cerb,

It stopped working last week, took it out today to have a look and I'm stumped as to what is wrong with it! I'm no auto electrician but I do have a bit of basic sparky know-how but this has me confused.


Removed the motor from the heater matrix, put a 12v supply directly on it and it works fine

Put a multimeter across the supply terminals with the motor disconnected, get 12v when I press the on switch, then 0v when I turn the swith off again

Plug the motor back in and NOTHING! Thought it might just need a push to get it started but that doesn't work either!

Maybe I am missing something obvious?

Any help is greatly appreciated as I have reached the boundaries of my electrical knowledge!

[dvs_dave]

The connector?

[Mattmoss]

Connects are all fine, continuity between the connector and the connection directly on the motor maybe I'm just being a bit a of spanner

[x 7usc]

hmmm, multi meter will require hardly any current to display voltage, try rigging up a high wattage bulb (headlamp) to the connections and see if the bulb lights up.
this may sound pointless but i have had this before with a blown fuse, turns out it had left carbon deposits when it had blown thus allowing voltage to track across but obviously not current, took a while to find as if you got voltage the fuse is ok right? WRONG in this case
could also be the same deal for the relay so try swapping with one known to work

HTH

[jhfozzy]

As mentioned, you need to put a load [like a bulb] on the supply as a "ghost" live or a bad earth can sometimes show a a good 12v on a multimeter.

[Mattmoss]

Thanks chaps I shall try that next then